1998 Expedition 4.6L

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Feb 13, 2002 | 05:59 PM

jcb67

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Joined: Feb 2002

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1998 Expedition 4.6L

Anyone out ther having idle problems? My idle drops from 800rpm to 500rpm several times while in park or at a stop light. I've been to the shop many times but Ford desnt have a clue because the check engine light never comes on....

Feb 14, 2002 | 10:11 AM

michaelskerrett

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From: Central Florida, USA

1998 Expedition 4.6L

You are not giving enough information. There may be nothing wrong at all. For example, if your A/C (or defrost depending on where you live)is running and the truck is standing still, as the compressor cycles a slight drop (about 200 rpm) can be observed while the clutch is engaged. As soon as it disengages the rpm will rise back to normal idle. You won't see that drop while in motion due to a whole lot of other things happening but the hourse power demand on the engine is the same while driving on the highway or idling in Park. Have a look under the hood with the A/C on while another watches the tachometer. I think you will see the drop and the compressor engage at the same time. Close the hood and keep trucking...all is well.

If not write back with more information and we can have another go at the problem.

Feb 14, 2002 | 05:29 PM

jcb67

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1998 Expedition 4.6L

[updated:LAST EDITED ON 14-Feb-02 AT 06:42 PM (EST)]Sorry I didnt include enough info. The idle fluctuates when the panel only or floor only is selected. I was told that any other position would cause the idle to fluctuate when the a/c compressor kicks on. Ford has already replaced some sensors and the problem still remains. Do you have any other suggestions?

Thanks

John B.
1998 Expedtion 4.6
Harrisburg, PA